In the case of Hong Kong, clearly Carrie Lam never lost confidence in the PRC's ability to keep her in power, so she and the other loyalists in the HK government never put up meaningful opposition.
But yes, I think that's the basic idea. There are many levers to political power. Sometimes people think that authoritarians rule by fiat, like a god, but they also are balancing and managing many political factors (though not so much the free will of the people).
Multiple overlapping reasons, some of which include:
- the military overthrows the rest of the executive/legislative powers
- Gross incompetence resulting in the government's self-destruction
- Financial collapse
- Secession
- Very strong external pressures (invasion, economic destruction, etc).
- Multiple violent insurrections straining executive resources and undermining the rule of law, allowing other groups to fill the role of the government.
Note that those necessary to take power are not always the same as those necessary to keep it; people often end up with something different than what they bargained for.
An excellent read: "The Dictator's Handbook". To say that politics is a dirty business is an understatement.
- multiple military mutinies, now suppressed, check
- the entirety of NK civil administration been sent to firing squad, or gulags multiple times, and rebuilt anew every time it fails
- financial collapse — you will never financially collapse if you can steal
- secession, you cannot secede in NK, even individually. They have machinegunners at the border, shooting everybody trying to run away
- NorKo been under every international sanction imaginable for 70 years.
- There are insurrections in NK almost every day. They are crushed, all, and every.
My point is, dictatorships, and monarchies do not simply topple, they have to be toppled.
Yes, by those next in line. They fall when those one step down from power takes it. That they might use the average citizen to gain power and that it might make it better for them than before is a side effect. It's the same in democratic elections. The average citizen never get the power, it is transferred to someone who might or might not be more aligned with their wishes.
That's not what secession means.
Sometimes in authoritarian regimes, a portion of the territory under controls realizes it is powerful enough to be its own master. The ensuing conflicts might then topple the whole thing. That's how the Ottoman Empire fell for example.
Disintegration is always a risk for large entity.
They don't topple, they are toppled.